Conventional vehicles, including utility vehicles and side-by-side vehicles, have an internal combustion engine that generates drive torque. To drive pistons of the engine, an air/fuel mixture combusts within cylinders and the air/fuel mixture is regulated via intake and exhaust valves. The intake valves are selectively opened to draw air into the cylinders, and the air is mixed with fuel to form the air/fuel mixture. To allow exhaust gas to exit from the cylinders after combustion, the exhaust valves are selectively opened at a specific time.
Continuously variable transmissions (CVTs) are typically installed in recreational vehicles, such as snowmobiles and all-terrain vehicles. The CVT provides an infinite number of different gears that are effective at transmitting torque from the engine to an output driveline of the transmission. The output driveline operatively couples the transmission to at least one ground engaging member.
However, due to a belted construction of the CVT, one of the drawbacks is that a drive belt of the CVT tends to wear out and become damaged prematurely when the drive belt is not broken in properly or used excessively under undesirable conditions. Since the drive belt solely transmits the engine power from a drive pulley to a driven pulley of the CVT, the drive belt is an important component of the CVT. Typically, the CVT drive belt is a V-belt, and is made from rubber, usually fiber-reinforced, that is rigid across but flexible along its length. During operation the drive belt undergoes extreme pressure and friction.
When the drive belt loses pressure between the sheaves of the CVT under high-load or over-load conditions, a slippage may occur causing belt damage, such as a spin-burn or hour-glassing event. For example, during the spin-burn event, a belt temperature may rapidly reach over 200 degrees Fahrenheit (° F.) without any warning, and may continue to rise up to 400° F. if no remedial action is taken. At that point, the drive belt is irreparably damaged, and without replacing the damaged drive belt, the vehicle cannot operate, thereby incurring increased maintenance costs and repair time.
As such, there are opportunities to develop an improved diagnostic system and method that can automatically detect or predict a fault of the drive belt before potential belt damage.